Luminous Landscape Forum
Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: hdomke on July 01, 2008, 11:18:09 pm
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This Medium Format forum has had a lot of discussion (and disagreement) on the value of higher bit-depth on Medium Format Cameras. To help clarify the issue, I asked a digital imaging expert: Tim Grey. He posted his answer in his Digital Darkroom Questions (DDQ) e-mail (http://www.timgrey.com/ddq/) today.
Conclusion: There is a difference with higher bit-depth Medium Format Digital Backs, but it tends to be very subtle, and digital 35mm SLRs continue to improve and narrow the gap
Here is the full text of his answer from the July 1 DDQ:
Images from a medium format digital back do indeed have the potential for greater dynamic range in the print. Of course, that potential isn't always realized, but in terms of the information captured, in a general sense medium format digital will still exceed the capabilities of digital SLR cameras to some extent.
The bit-depth is certainly a contributing factor, but just because you have higher bit-depth doesn't mean you necessarily have greater dynamic range. For example, you could theoretically use the imaging sensor from a very old digital camera that wasn't able to capture any real dynamic range (think in terms of a really old mobile phone camera) and update the analog-to-digital (A/D) converter to create a 16-bit per channel file from that image. You now have high-bit data (sort of), but it is based on information captured from the sensor that is lacking significantly. The point here is that the bit-depth is really more about the size of the container for the image data, and isn't necessarily indicative of the data you are actually capturing. Dynamic range is the measure of the difference between the brightest and darkest values that can be recorded.
In order to understand the nature of the data you're capturing, you need to look at the imaging sensor itself, not just the way the data captured by the sensor is being converted. There are a variety of factors that affect dynamic range in an imaging sensor, but one of the specifications you can look at to get a sense of the relative dynamic range capabilities of an imaging sensor are is the size of the individual pixels on the imaging sensor (the pixel pitch), which is measured in microns. Larger photodetectors on the imaging sensor are capable of capturing more electrical charge (which is how the light it "sees" is recorded), and thus are able to capture a broader range between "empty" (minimum value) and "full" (maximum value). That translates into greater dynamic range (generally speaking), so in general larger photodiodes are a good thing (from the perspective of dynamic range and noise anyway), within reason of course. And of course for a given sensor size (physical dimensions) as you increase resolution you reduce the size of the individual photodetectors, so this is always something the camera manufacturers (and imaging sensor manufacturers) have to contend with.
To give you a sense of the potential of medium format imaging sensors, it can be helpful to consider the relative size of the photodetectors in real terms. One of the top professional digital SLR cameras is the Canon EOS 1Ds Mark III, which offers 21.1 megapixels and has a pixel pitch of 6.4 microns. The PhaseOne P25+ digital bak, which offers an effective resolution of 22 megapixels, has a pixel pitch of 9 microns. While these are both incredibly small sizes, as you can see the medium format digital back has much larger photodetectors in relative terms. At the lower end, a typical point-and-shoot digital camera with 7.1 megapixels has a pixel pitch of about 1.9 microns.
Of course, when it comes to the print there are other limitations. You can have all the bit-depth and dynamic range in the world, and if you're printer can't reproduce all those values the data isn't really worth much in the context of that print. So, while a medium format digital back is most certainly going to give you more information in your digital captures, today's printers aren't really capable of reproducing that information to the extent that it makes a significant difference in the final print. There is a difference, but it tends to be very subtle, and digital SLRs continue to improve and narrow the gap. There's no question there are inherent benefits to the imaging sensor used in a medium format digital back, but technology is developing to the point that the benefit is relatively modest, especially when viewed in context of the pace of change in digital photography over the last ten years.
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Note: there are other threads that touch on this topic, but they started to meander and were not as specific. This topic deals just with bit-depth. Here are links to the other topics:
RAW files: 1Ds3 and Phase P30+ (http://luminous-landscape.com/forum/index.php?showtopic=26025)
Medium Format vs 35mm - Just More Pixels? (http://luminous-landscape.com/forum/index.php?showtopic=26124)
Can Stitching 1DsMk3 files = Med Format Quality (http://luminous-landscape.com/forum/index.php?showtopic=25937)
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whatever.
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whatever.
[a href=\"index.php?act=findpost&pid=204931\"][{POST_SNAPBACK}][/a]
You know, I think I'm going to go to Papaya King tomorrow for the Depression Special. I really like their hot dogs. I might also hit Century and buy a new belt.
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You know, I think I'm going to go to Papaya King tomorrow for the Depression Special. I really like their hot dogs. I might also hit Century and buy a new belt.
[a href=\"index.php?act=findpost&pid=204932\"][{POST_SNAPBACK}][/a]
15 minutes and I'm still ROTFLMAO!
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15 minutes and I'm still ROTFLMAO!
[a href=\"index.php?act=findpost&pid=204934\"][{POST_SNAPBACK}][/a]
My pleasure! I aim to please.
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dood - bit depth doesn't matter at all. just buy a 1Ds and be done with it...
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Yaaaaawn!
It misses the point entirely. The benefit of having a 16-Bit MFDB is that the file is more elastic / flexible.
Also far improved on long exposures.
I *think* (note sarcasm) it has been recommended before to go out and take some pictures. Work with them, then you will see.
If you don't, it doesn't matter, therefore you are comfortable with the 35mm choice.
Ok?
Jo S.x
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It misses the point entirely. The benefit of having a 16-Bit MFDB is that the file is more elastic / flexible.
[a href=\"index.php?act=findpost&pid=204963\"][{POST_SNAPBACK}][/a]
Exactly. Plus I wouldn't even trust that testers know how to switch off default curves in their raw processing apps.
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The point here is that the bit-depth is really more about the size of the container for the image data
You can have all the bit-depth and dynamic range in the world, and if you're printer can't reproduce all those values the data isn't really worth much in the context of that print.
today's printers aren't really capable of reproducing that information to the extent that it makes a significant difference in the final print.
[a href=\"index.php?act=findpost&pid=204921\"][{POST_SNAPBACK}][/a]
Exactly - the container is larger and when you know how to fill it up (as most owners of MFDB's would do) you have more to play with. No one uses a file without a curve or adjustment applied...
It's a fair assumption that those who have shelled out big bucks for a MFDB system will not be cutting corners with their printing processes either.
Getting that last bit of a quality, only available at the 'top' of any endeavour is always going to require more resources for less return - it's why fewer people go there. The differences may be subtle but significant. Often that difference only appears 'subtle' at first glance...
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Wow, what are you on some sort of ridiculous crusade to justify your own unwillingness/inability to invest in a DB? The problem is that if you have ever worked a file hard in post from both 35mm and a DB the difference is blatantly obvious. So who are you trying to convince here, yourself perhaps? I use both on a daily basis and have no delusion that one can substitute the other, instead I embrace the pros and cons and use them for different things.
Enough of this BS already.
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...and in the end it's always about the money... as a good man used to say; " if you have to ask for the price, it is to expensive for you" and one can always find a reason not to spent a certain amount of money. i think it is useless to keep on answering those questions: all what there is to say is more than a million times written....
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I just love the cause and effect with web forums these days... a poster takes the time to serve up some banter on a "grey area" topic and most viewers either walk out of the room yelling BS or they instantly send back an insult. Reminds me of the senate on planet of the apes.
If you don't have something good to say... then just don't say anything.
I own both a 1ds3 and a p45+V and do notice a difference in final image quality as well.... but each "system" has it's merits... i.e I can't get the look (love) of the 85mm f1.2 wide open on the 1ds3 when I use the MFDB.... Likewise, I can't get the crispness (high detail) of the hyper focal abilities of the MFDB stopped down around f16 when I shoot with the 1ds3.
I also can't match the wide angle of view with wide lens' on the 1ds3 when I choose the "V" MFDB.
But..... I can say that when I use the 1ds3 as it should be used ( raw to 16 bit tiff & good glass... + proper technique ) it closes the gap considerably from the 1ds2 to MFDB.
As to higher bit depth mattering?.... If you are striving for the best image you can capture today? YES!
If your shooting technique right for the situation and nail your exposure without having to adjust much in post?.... NOT REALLY.
If you tend to do "looks" in post that require you to mangle your file around a bit ( like the infamous Dragon look )..... YES
If you shoot reproduction work of paintings.... YES
If you shoot hyper-real landscape.... YES
If you shoot fine art..... ( dirty look ) NO.... ( clean hyper-real look ) YES
To quote the Beatles.... "it's getting better all the time"
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if you had only 1 bit - whould that make a difference?
If your answer is 'yes', you should understand why 16 is better than 8.
if your answer is 'no', well, use 1 bit then or ask yourself if 0 bits would make a difference instead.
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There was a relatively technical article recently referenced in one of the ETTR threads and my recollection is that at some point, at around 12-14 bits, noise renders any "larger container" superfluous, at least with today's AD converters.
-
This Medium Format forum has had a lot of discussion (and disagreement) on the value of higher bit-depth on Medium Format Cameras. To help clarify the issue, I asked a digital imaging expert: Tim Grey. He posted his answer in his Digital Darkroom Questions (DDQ) e-mail (http://www.timgrey.com/ddq/) today.
Conclusion: There is a difference with higher bit-depth Medium Format Digital Backs, but it tends to be very subtle, and digital 35mm SLRs continue to improve and narrow the gap
Here is the full text of his answer from the July 1 DDQ:
Images from a medium format digital back do indeed have the potential for greater dynamic range in the print. Of course, that potential isn't always realized, but in terms of the information captured, in a general sense medium format digital will still exceed the capabilities of digital SLR cameras to some extent.
To give you a sense of the potential of medium format imaging sensors, it can be helpful to consider the relative size of the photodetectors in real terms. One of the top professional digital SLR cameras is the Canon EOS 1Ds Mark III, which offers 21.1 megapixels and has a pixel pitch of 6.4 microns. The PhaseOne P25+ digital bak, which offers an effective resolution of 22 megapixels, has a pixel pitch of 9 microns. While these are both incredibly small sizes, as you can see the medium format digital back has much larger photodetectors in relative terms. At the lower end, a typical point-and-shoot digital camera with 7.1 megapixels has a pixel pitch of about 1.9 microns.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=204921\")
The responses thus far to thread have been largely pathetic and have provided no objective information. Tim Grey's essay is good, but he too provides no objective information.
Dynamic range and useful bit depth is limited by noise, and increased bit depth will not be helpful if the useful levels in the raw image are obscured by noise. A good analysis of this matter is presented by [a href=\"http://theory.uchicago.edu/~ejm/pix/20d/tests/noise/index.html]EJ Martin.[/url]
Discussion with presentation of additional data is presented in a DPReview thread listed below. The discussion is concerning the Nikon D3, whose pixel size is 8.4 microns, slightly smaller than the 9 microns of the referenced 22 megapixel medium format camera, but larger than the pixel size of the P45+ 39 MP back (6.8 microns). The same principles apply.
DP Review Thread (http://forums.dpreview.com/forums/read.asp?forum=1021&message=28190287)
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You know, I think I'm going to go to Papaya King tomorrow for the Depression Special. I really like their hot dogs. I might also hit Century and buy a new belt.
[a href=\"index.php?act=findpost&pid=204932\"][{POST_SNAPBACK}][/a]
me, beeing back in gauting ( closed to munich/ germany ) just have eaten a great steak with
rice at the schlosscafe.
having my back resting in my bag, so i cant discuss about its 16bit qualities.
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me, beeing back in gauting ( closed to munich/ germany ) just have eaten a great steak with
rice at the schlosscafe.
having my back resting in my bag, so i cant discuss about its 16bit qualities.
[a href=\"index.php?act=findpost&pid=205048\"][{POST_SNAPBACK}][/a]
That sounds fantastic! My Depression Special was really good, and really cheap. I'm sure it wasn't as good as your steak, but man, there is something about a good hot dog that makes me really happy. Last time I was in Munich I had a great lunch of Weisswurst, spicy brown mustard, and a litre of Warsteiner. Man that was good!
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me, beeing back in gauting ( closed to munich/ germany ) just have eaten a great steak with
rice at the schlosscafe.
having my back resting in my bag, so i cant discuss about its 16bit qualities.
[a href=\"index.php?act=findpost&pid=205048\"][{POST_SNAPBACK}][/a]
Mmmmm...mmm. Just had a nice salad with a tad too much feta.
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Beer and food pairing. Interesting article http://www.allaboutbeer.com/features/243beerandfood.html (http://www.allaboutbeer.com/features/243beerandfood.html)
"The flavor hook is the part of the beer’s flavor and aroma that matches, harmonizes or accentuates the flavors in your food. When the flavors meet on your tongue, they "recognize" each other and this creates a harmony.
Sometimes, rather than harmony, you’re setting up a pleasant contrast. Beer can have flavors of caramel, coffee, chocolate, bread, bananas, limes, herbs, smoke or raspberries–there’s a lot here to work with."
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There was a relatively technical article recently referenced in one of the ETTR threads and my recollection is that at some point, at around 12-14 bits, noise renders any "larger container" superfluous, at least with today's AD converters.
You can't simply compare DSLRs and MFDBs by bit depth, or say that anything beyond 12 to 14 bits is meaningless - as with most things in life, it's more complicated than that. People who want to boil this debate down to simple black and white answers are only deluding themselves.
A/Ds come in various quality levels, depending on cost and sampling rate, among other things. You can certainly get very high sampling rate 16-bit A/Ds, suitable for imaging applications, with 2 to 4 bits of noise, i.e. the A/D itself generates 2 to 4 bits of noise, leaving 12 to 14 bits of real, noise-free data (obviously any noise in the signal being sampled by the A/D just gets passed along, along with the additional noise contributed by the A/D itself). These are relatively expensive, however. Lower cost A/Ds typically generate more bits of noise, delivering fewer bits of noise-free data. You can get up to 24 bit A/Ds with more moderate sampling rates with similar noise capabilities, i.e. you get 20 to 22 bits of real, noise free data (by noise free, I mean noise contributed by the A/D itself - any image sensor output will almost certainly have plenty of noise in the lower bits if you are sampling it at 24 bits).
So if you are going to argue the merits of bit depth, the first thing you have to ask is what is the quality of the A/Ds you are using. All 14-bit A/Ds or 16-bit A/Ds are not created equal. I don't have any hard data to back this up, but I'm pretty sure all of the new 14-bit DSLRs are using actual 14-bit A/Ds, which means they are getting, at best, 10 to 12 bits of real, noise-free data, assuming they used expensive low noise A/Ds. Furthermore, I believe that at least some of the MFDBs are using more expensive 16-bit A/Ds (and maybe even higher bit depths), and downsampling to 14-bits (throwing away the noisiest bits), and then saving those 14-bits as 16-bit RGB values (a bit confusing, I know). If true, this means MFDBs are getting 12 to 14 bits of real, noise free data (or more, if they are using high quality higher bit depth A/Ds, and then truncating off the lower bits for storage as 16-bit RGB).
Given the price differential between DSLRs and MFDBs, I also suspect DSLRs are using lower priced, and hence noisier A/Ds, while the more expensive MFDBs can afford to use higher cost, and hence less noisy A/Ds. This is simply guesswork on my part, but it seems reasonable. So again, not all A/Ds are created equal. I find it very plausible that the higher cost MFDBs are using more expensive, lower noise A/Ds in their processing path than the DSLRs are.
Anyway, my point is that making a simplistic argument that 12-14 bits is as high as you can go is just that - simplistic. It certainly doesn't take into account the parts budget that the designer has to work with, and the quality of the parts he is forced to use for cost reasons, or the quality of the parts he can afford to use because he is designing them into a higher priced product. In other words, part of the reason MFDBs are so expensive is that they use higher quality, lower noise components (of course, there are economies of scale, etc, but parts cost is also a factor).
And there are a host of other noise sources that have to be accounted for, in addition to sensor noise and A/D noise. There's amplifier noise, and power circuit noise, and coupling noise. All of these are price sensitive - the higher your parts budget, the lower noise parts you can afford to use. And most of these get worse as temperatures rise, so your camera or back has to have good thermal management and heat dissipation to get the best out of the equipment.
So as I said at the beginning - You can't simply compare items by their bit-depth, or say that 12 to 14 bits is the effective limit of what you can have. It simply isn't so.
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Beer and food pairing. Interesting article http://www.allaboutbeer.com/features/243beerandfood.html (http://www.allaboutbeer.com/features/243beerandfood.html)
"The flavor hook is the part of the beer’s flavor and aroma that matches, harmonizes or accentuates the flavors in your food. When the flavors meet on your tongue, they "recognize" each other and this creates a harmony.
Sometimes, rather than harmony, you’re setting up a pleasant contrast. Beer can have flavors of caramel, coffee, chocolate, bread, bananas, limes, herbs, smoke or raspberries–there’s a lot here to work with."
[a href=\"index.php?act=findpost&pid=205058\"][{POST_SNAPBACK}][/a]
Thanks for th link. My friend owns a bar on McDougal, 124 Rabbit Club. Its a beer/wine bar. He was pawning off this RauschenBier, a German beer that complies with the Reinheitsgebot but adds a twist to the flavor. Tastes like a campfire. Kind of gross. I'll check your link to see if there is pairing for RauchenBier.
Abita Amber goes really, really well with spicy Louisiana food. Maybe I'll make Jambalyia tonight . . .
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That sounds fantastic! My Depression Special was really good, and really cheap. I'm sure it wasn't as good as your steak, but man, there is something about a good hot dog that makes me really happy. Last time I was in Munich I had a great lunch of Weisswurst, spicy brown mustard, and a litre of Warsteiner. Man that was good!
[a href=\"index.php?act=findpost&pid=205056\"][{POST_SNAPBACK}][/a]
the problem with traditional bavarian food in our digital stoneage is that they just use 11 of their 20 available bits. the rest is beer.
and this makes me feel somehow crazy if i take more than 6 bits of it. man ....
and this are 9 !!!!!!!!!
maybe i should eat my 5d.
its not water- resistant so all the beer is running out of it even if you fill in 12bit. or to go with the 1ds3?
any advice highly appreciated.
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I *think* (note sarcasm) it has been recommended before to go out and take some pictures. Work with them, then you will see.
[a href=\"index.php?act=findpost&pid=204963\"][{POST_SNAPBACK}][/a]
Your suggestion makes since; I agree. As I have said on my previous posts, I actually have gone out and done side-by-side comparisons. Specifically, I have compared my 1DsMk3 to the Phase One P45+ and also the Hasselblad 39 MP camera.
The reason I have been persistent with my posts here is that I was surprised at how little difference there was. But my experience was limited to just a few test shots, so I was reluctant to base my decisions on a limited experience. I thought that those of you who use these cameras every day could shed some light (theoretical and practical) on the differences.
When I enlarged these images to ten-feet wide and then took a section from the center to print, the difference were much less than I expected. Clearly the MF backs shows more fine detail, but with a more vigorous application of Unsharp Masking the difference was impossible for me to appreciate at normal viewing distance (3-feet).
Regarding shadow detail, highlight detail and noise, I could see no difference whatsoever. Granted, these pictures were perfectly exposed and did not need radical adjustments; but in the real world, my exposures are almost always correct.
Before I go and spend large amounts of money on a new camera system and spend the hours it takes to learn how to use it, I want to reasonable assurance that the quality differences will be apparent to me and my clients.
Based on what I have seen with my own experience and have learned so far on this forum, I remain unconvinced that upgrading to Medium Format is worth it for my business. But I am trying to remain open minded. My business incidentally is to sell large nature photographs to commercial clients. The prints are make on an Epson Stylus Pro 11880 and sizes range to 5 x 8-feet and larger.
If you disagree with my conclusion, please try convince me otherwise.
Thanks!
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the problem with traditional bavarian food in our digital stoneage is that they just use 11 of their 20 available bits. the rest is beer.
and this makes me feel somehow crazy if i take more than 6 bits of it. man ....
and this are 9 !!!!!!!!!
maybe i should eat my 5d.
its not water- resistant so all the beer is running out of it even if you fill in 12bit. or to go with the 1ds3?
any advice highly appreciated.
[a href=\"index.php?act=findpost&pid=205062\"][{POST_SNAPBACK}][/a]
I'd wait for the new Nikon. 14 bit, 24 megapixels, water proof, such that it will hold a liter of Pilsner or 750 cl of heavier Belgian Trappist or Bavarian dopple bock. I heard, and I can't confirm or tell you who told me (it was Annie Leibowitz) that the new Nikon will have a sausage maker built into the rear display. Nice. Real nice.
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I'd wait for the new Nikon. 14 bit, 24 megapixels, water proof, such that it will hold a liter of Pilsner or 750 cl of heavier Belgian Trappist or Bavarian dopple bock. I heard, and I can't confirm or tell you who told me (it was Annie Leibowitz) that the new Nikon will have a sausage maker built into the rear display. Nice. Real nice.
[a href=\"index.php?act=findpost&pid=205066\"][{POST_SNAPBACK}][/a]
wow.
hicks.
urg ... ups.
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If you disagree with my conclusion, please try convince me otherwise.
Henry, if you've already made up your mind, why continue to beat a dead horse? Act on your conclusions.
I'm not dissing you here, I'm just confused about where you're coming from and what your purpose in posting this thread is. A lot of people on this forum think you are just trying to trash MFDBs, that you are carrying the torch for Canon. Hence the hostility you get on this forum.
Personally, I've compared images from my D3 and a friends 1DsIII. I'll take the D3's images anytime. Please try to convince me otherwise.
Personally, I've compared D3 and 1DsIII images with images from my P45+. I'd much rather have the P45+ images. Please try to convince me otherwise.
Personally, I find fall supperior to spring. Please try to convince me otherwise.
Personally, I find classic coke much better than pepsi. Please try to convince me otherwise.
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"You have chosen to ignore hdomke. View this post · Un-ignore hdomke"
TMARK, I know they're supposed to be so good and all, but I've never been a fan of German beir in general. A friend of mine is German and she's always having us meet up at Zum Schneider and Loreley and the like. Fine places, but I'd rather a nice microbrew most often. I'll have to check out Abita Amber. Big fan of ambers, bitters, browns and pale ales.
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"You have chosen to ignore hdomke. View this post · Un-ignore hdomke"
TMARK, I know they're supposed to be so good and all, but I've never been a fan of German beir in general. A friend of mine is German and she's always having us meet up at Zum Schneider and Loreley and the like. Fine places, but I'd rather a nice microbrew most often. I'll have to check out Abita Amber. Big fan of ambers, bitters, browns and pale ales.
[a href=\"index.php?act=findpost&pid=205072\"][{POST_SNAPBACK}][/a]
i am with mort in this case:
"Personally, I find classic coke much better than pepsi. "
did you realize that he is saying CLASSIC ?
not sinar, not leaf, not phase, not hassy.
CLASSIC !!!
means analog.
thats out. isnt it? no bits. no 3d. no 5d. no canon.
classic.
just realized that it seems to me that the canon even offers 5D.
with my backs i only get 3D !!!
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i am with mort in this case:
"Personally, I find classic coke much better than pepsi. "
did you realize that he is saying CLASSIC ?
not sinar, not leaf, not phase, not hassy.
CLASSIC !!!
means analog.
thats out. isnt it? no bits. no 3d. no 5d. no canon.
classic.
just realized that it seems to me that the canon even offers 5D.
with my backs i only get 3D !!!
Well, I do complain if I find bits in my classic coke. So I guess you're right, that does mean it's analog.
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"You have chosen to ignore hdomke. View this post · Un-ignore hdomke"
TMARK, I know they're supposed to be so good and all, but I've never been a fan of German beir in general. A friend of mine is German and she's always having us meet up at Zum Schneider and Loreley and the like. Fine places, but I'd rather a nice microbrew most often. I'll have to check out Abita Amber. Big fan of ambers, bitters, browns and pale ales.
[a href=\"index.php?act=findpost&pid=205072\"][{POST_SNAPBACK}][/a]
My German friends like Coors. Seriously. They are mainly from the Luneberg Heath/North German Plane area, but still. "Coors, its crip and refreshing. From the Rockies!" I'm usually shocked.
I myself love the ambers and ales. Abita is like a smoother, more "hopsie" if you will, version of New Castle, which I also like. I have a soft spot for Louisiana products, and Abita is one of the best. Dixie, on the other hand, is one of the worst.
I do like Bavarian beer, but the wheats. I do not like lagers, and can obly tepidly support pilsners.
Sometimes I like King Kobra, mainly because of the Billy D commercials. I'm also known to drink Old English on occassion, but only because I really really like Ice Cube.
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I'd wait for the new Nikon. 14 bit, 24 megapixels, water proof, such that it will hold a liter of Pilsner or 750 cl of heavier Belgian Trappist or Bavarian dopple bock. I heard, and I can't confirm or tell you who told me (it was Annie Leibowitz) that the new Nikon will have a sausage maker built into the rear display. Nice. Real nice.
[a href=\"index.php?act=findpost&pid=205066\"][{POST_SNAPBACK}][/a]
D'y' know, I haven't had a Trappist triple in a long time. Wonder are there any places here in Northern Ireland you can get that?
It's a bit of a poor show just having Magners and Pizza, when I read what all you guys are having.
Mind you, the food mixer has a 4 bit processor. Do you think the dough would be better if it had a 16 bit processor instead?
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My German friends like Coors. Seriously. They are mainly from the Luneberg Heath/North German Plane area, but still. "Coors, its crip and refreshing. From the Rockies!" I'm usually shocked.
I myself love the ambers and ales. Abita is like a smoother, more "hopsie" if you will, version of New Castle, which I also like. I have a soft spot for Louisiana products, and Abita is one of the best. Dixie, on the other hand, is one of the worst.
I do like Bavarian beer, but the wheats. I do not like lagers, and can obly tepidly support pilsners.
Sometimes I like King Kobra, mainly because of the Billy D commercials. I'm also known to drink Old English on occassion, but only because I really really like Ice Cube.
[a href=\"index.php?act=findpost&pid=205078\"][{POST_SNAPBACK}][/a]
can anyone explain to me why i should work with a digital back if it only offers 3D,
meanwhile my much cheaper canon offers 5D. aside from its better iso performance?
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Mind you, the food fixer has a 4 bit processor. Do you think the dough would be better if it had a 16 bit processor instead?
It probably wouldn't be as lumpy - you know, with 16 bits, you'd get a smoother texture.
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can anyone explain to me why i should work with a digital back if it only offers 3D,
meanwhile my much cheaper canon offers 5D. aside from its better iso performance?
[a href=\"index.php?act=findpost&pid=205081\"][{POST_SNAPBACK}][/a]
LOL!
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can anyone explain to me why i should work with a digital back if it only offers 3D,
meanwhile my much cheaper canon offers 5D. aside from its better iso performance?
[a href=\"index.php?act=findpost&pid=205081\"][{POST_SNAPBACK}][/a]
I think you've had a little to much Bavarian doppelbock, Rainer!
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can anyone explain to me why i should work with a digital back if it only offers 3D,
meanwhile my much cheaper canon offers 5D. aside from its better iso performance?
[a href=\"index.php?act=findpost&pid=205081\"][{POST_SNAPBACK}][/a]
Well, my Phase has a bottle opener. I heard Sinarbacks have an adapter system such that you can add a bottle opener to any MF camera. The 5D really only has 2D, anyway, because 3 of the D of the 5D are wasted, empty calories.
And Jon, a 16 bit food processor would make a much more layed, textured dough that would stand up to more stretching once processed.
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Well, my Phase has a bottle opener. I heard Sinarbacks have an adapter system such that you can add a bottle opener to any MF camera. The 5D really only has 2D, anyway, because 3 of the D of the 5D are wasted, empty calories.
And Jon, a 16 bit food processor would make a much more layed, textured dough that would stand up to more stretching once processed.
[a href=\"index.php?act=findpost&pid=205085\"][{POST_SNAPBACK}][/a]
no. the 5D has a certain 5D look. if you dont see it its not worth to discuss it with you.
sorry for that.
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Imagine the look of the 40D......
8X the look of your 5D
no. the 5D has a certain 5D look. if you dont see it its not worth to discuss it with you.
sorry for that.
[a href=\"index.php?act=findpost&pid=205088\"][{POST_SNAPBACK}][/a]
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I wish our Australian beer makers adopted some of those fine European brewing techniques...
We do have good wine though.
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Some sobering facts
The "digital imaging expert" seems to understand of this subject about as much as most of the posters above, which is not much (if I am very generous).
Now perhaps it is time to consider some facts.
If and how far 16 bits are useful with MFDBs is a complicated matter, in most cases impossible to prove in either direction. I can prove on images of *certain* MFDBs, that there *is* a difference between 14bit and 16bit (slightly less noise in 16bit), but that proof shows, that the difference is *very, very tiny*, in fact it is useless.
The question needs to be adjusted a bit in order to become reasonable:
do MFDBs need greater bit depth than DSLRs?
When analysing for example Canon 1DsMkIII images, the same can be said: the difference between 12bit and 14bit is there, but very small (note: even so I am a proponent of 14bit recording).
When comparing 16bit, 14bit and 12bit images of a Sinar eM54, it can be shown, that reducing to 12bit does cause practical image degradation.
It is clear, that the larger dynamic range of some MFDBs *requires* more bits than a camera with 2 stops lower dynamic range.
However, the most sobering fact is, that the Phase One cameras' last two bits are not only useless, but they are *detrimental* to the image. Luckily, the raw processors don't make any use of those bits, except in extreme circumstances (that's what caused Edmund complain about striations with his P45+).
The following captures depict three segments of the image CF000841, shot by a Phase One P30+ by the fellow LL poster 203. The first one shows the original, with +3 1/2 EV. The second one shows the 15th bit only and the third one is created by the 16th bit only (i.e. the lowest order bit) . The next four captures show two other crops, with only the 15th respectively 16th bit.
The waves and horizontal strips are artifacts of the sensor, as is the vertical separation line, caused by the "stitching" of the sensor chips.
These captures demonstrate, that the two low order bits of Phase One raw files *must not* be used (this is not a speciality of the P30+, I saw teh same on the P25+ and P45+ as well). In other words: the 16 bit recording is worthless with these cameras.
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Some sobering facts
The "digital imaging expert" seems to understand of this subject about as much as most of the posters above, which is not much (if I am very generous).
Now perhaps it is time to consider some facts.
If and how far 16 bits are useful with MFDBs is a complicated matter, in most cases impossible to prove in either direction. I can prove on images of *certain* MFDBs, that there *is* a difference between 14bit and 16bit (slightly less noise in 16bit), but that proof shows, that the difference is *very, very tiny*, in fact it is useless.
The question needs to be adjusted a bit in order to become reasonable:
do MFDBs need greater bit depth than DSLRs?
When analysing for example Canon 1DsMkIII images, the same can be said: the difference between 12bit and 14bit is there, but very small (note: even so I am a proponent of 14bit recording).
When comparing 16bit, 14bit and 12bit images of a Sinar eM54, it can be shown, that reducing to 12bit does cause practical image degradation.
It is clear, that the larger dynamic range of some MFDBs *requires* more bits than a camera with 2 stops lower dynamic range.
However, the most sobering fact is, that the Phase One cameras' last two bits are not only useless, but they are *detrimental* to the image. Luckily, the raw processors don't make any use of those bits, except in extreme circumstances (that's what caused Edmund complain about striations with his P45+).
The following captures depict three segments of the image CF000841, shot by a Phase One P30+ by the fellow LL poster 203. The first one shows the original, with +3 1/2 EV. The second one shows the 15th bit only and the third one is created by the 16th bit only (i.e. the lowest order bit) . The next four captures show two other crops, with only the 15th respectively 16th bit.
The waves and horizontal strips are artifacts of the sensor, as is the vertical separation line, caused by the "stitching" of the sensor chips.
These captures demonstrate, that the two low order bits of Phase One raw files *must not* be used (this is not a speciality of the P30+, I saw teh same on the P25+ and P45+ as well). In other words: the 16 bit recording is worthless with these cameras.
[a href=\"index.php?act=findpost&pid=205107\"][{POST_SNAPBACK}][/a]
I really like Sabretts.
[attachment=7301:attachment][attachment=7301:attachment][attachment=7301:attachm
ent][attachment=7301:attachment][attachment=7301:attachment]
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Henry, if you've already made up your mind, why continue to beat a dead horse? Act on your conclusions.
I'm not dissing you here, I'm just confused about where you're coming from and what your purpose in posting this thread is. A lot of people on this forum think you are just trying to trash MFDBs, that you are carrying the torch for Canon. Hence the hostility you get on this forum.
[a href=\"index.php?act=findpost&pid=205070\"][{POST_SNAPBACK}][/a]
Mort,
I appreciate your comment and will stop posting on this forum about this topic.
I'm sorry if people on this forum thought I was trying to trash MFDBs. I had no such intent. I was seriously considering buying a MF system, but wanted to look carefully before I jumped. My limited testing did not show a clear difference when comparing my 1DsMk3 and a couple of MF backs. That surprised me. I wanted to hear from those with more experience.
Nor am I wanting to promote Canon. I've happily owned and used Hasselblad, Nikon and Canon systems over the last three decades. All have served me well.
Thanks to all who provided feedback.
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They are world class because they are artists in the commercial realm. They, for the most part, don't give a rat's ass about the scientific bullshit
I am very impressed, but I don't know, for what you mean it.
Is this an explanation for the relative low level of digital literacy, or an excuse for the schoolyard bully like behaviour?
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Henry,
I think this is a fair comment to make: By the looks of your work, you won't really see much difference in looking at files between a Canon 1DsIII and MFDBs. You aren't pushing your files past straight forward exposures and in no way pushing the abilities of any of these cameras through your chosen content of shooting. For people who are truly "bending" their files for look and style (very evident in fashion and many other genres of photography), then the advantages of MFDBs or just higher bit depth will show for sure.
For Panopeeper,
Here is a "sobering fact", you and I and many more here are graced with the participation of some world class photographers on this forum. They are world class because they are artists in the commercial realm. They, for the most part, don't give a rat's ass about the scientific bullshit. ART and CREATIVITY are, in my view and many talented photographers' views, the foremost keys to unlocking photography, not all this mumbo jumbo "anal-yzing".
I have a degree in Chemistry (it was easy for me), I was an organic chemist for several years. Science is soul-less without creativity of how to use it. Photography is soul-less without creativity to harness vision. In the end, the vision can last a lifetime or many lifetimes; gadgets, tools, programs, and anything else which in and of itself accomplishes nothing without human mastery will erode rapidly.
It's all about the image. I can look at the work from talented photographers (a hell of a lot more talented than I am) and see that they had that image in their head. The camera, hardware, software, film, scanners, lighting, etc. were just the means to the end, nothing else.
I'll also add, I stick around here because the forum is about problem solving so we can work more fluidly to create our art, not problem making. There are a lot of photographers with different shooting methods and in different photo genres, all that put together makes for a wealth of info. 1's, 0's, bits are just the least informational items possible.
[a href=\"index.php?act=findpost&pid=205159\"][{POST_SNAPBACK}][/a]
Well said.
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All 14-bit A/Ds or 16-bit A/Ds are not created equal. I don't have any hard data to back this up, but I'm pretty sure all of the new 14-bit DSLRs are using actual 14-bit A/Ds, which means they are getting, at best, 10 to 12 bits of real, noise-free data, assuming they used expensive low noise A/Ds. Furthermore, I believe that at least some of the MFDBs are using more expensive 16-bit A/Ds (and maybe even higher bit depths), and downsampling to 14-bits (throwing away the noisiest bits), and then saving those 14-bits as 16-bit RGB values (a bit confusing, I know).
Mort54, you seem to be implying that all ADCs are adding 2 bits of noise as a rule of thumb but this is not true. In fact it is even conceivable that a poor quality 16 bit SDC will have a worse SNR than a 14 bit ADC.
Just look at this spec chart from Texas Instruments of 16bit ADCs. The SNR on these ranges from 79 to 95dB! That nearly 3 bits difference.
http://focus.ti.com/paramsearch/docs/param...R_2000084|EQ|16 (http://focus.ti.com/paramsearch/docs/parametricsearch.tsp?family=analog&familyId=390&uiTemplateId=NODE_STRY_PGE_T&virtualTreeURL=D_PARAMETER_2000084|EQ|16)
So at least we can agree that not all ADCs are created equal. It is quite possible for a stunning 14bit circuit to outperform a poor 16bit competitor.
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Granted, these pictures were perfectly exposed and did not need radical adjustments; but in the real world, my exposures are almost always correct.
Did you test scenes with high dynamic range?
If the sensors from two cameras have different DR then how do you compare the exposures? Do you consider them equal when they are both equally weighted around 50%, or both exposed to just under the point of clipping? These are two different methods, and the former does not take full advantage of the higher DR sensor.
Actually you provide so little data about this comparison that I can't make any useful judgments at all, sorry.
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can anyone explain to me why i should work with a digital back if it only offers 3D,
meanwhile my much cheaper canon offers 5D. aside from its better iso performance?
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=205081\")
Rainer, I hope you haven't wasted your money already. You can get 6D for only $70!
[a href=\"http://www.digitalgraphicsresources.com/index.asp?PageAction=VIEWPROD&ProdID=664]http://www.digitalgraphicsresources.com/in...PROD&ProdID=664[/url]
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The following captures depict three segments of the image CF000841, shot by a Phase One P30+ by the fellow LL poster 203. The first one shows the original, with +3 1/2 EV. The second one shows the 15th bit only and the third one is created by the 16th bit only (i.e. the lowest order bit) . The next four captures show two other crops, with only the 15th respectively 16th bit.
[a href=\"index.php?act=findpost&pid=205107\"][{POST_SNAPBACK}][/a]
Interesting. You'd think that P1 would pad out the 2 least significant bits, even though this really doesn't have an impact in the real world unless you are stretching/pushing the files hard.
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Rainer, I hope you haven't wasted your money already. You can get 6D for only $70!
http://www.digitalgraphicsresources.com/in...PROD&ProdID=664 (http://www.digitalgraphicsresources.com/index.asp?PageAction=VIEWPROD&ProdID=664)
[a href=\"index.php?act=findpost&pid=205315\"][{POST_SNAPBACK}][/a]
no. i still dont want to paint my images myself although i am aware that these deliver the best bit depth for its money. but after photokina i will think again about that.
did you saw this ?
[attachment=7324:attachment]
true 9 colors roylgglccdcb sensor which increase its resolution without any interpolation.
( stands for red-orange-yelow-lightgreen-green-lightcyan-cyan-darkcyan-brown sensor )
anyway still not perfect for b+w.
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"I really like Sabretts."
worlds best hotdog by far...altho I like me a Hebrew National once in a while as well...
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Mort54, you seem to be implying that all ADCs are adding 2 bits of noise as a rule of thumb but this is not true.
I certainly didn't mean to imply that, and thought I was quite clear that noise figures vary considerably across different A/Ds. I specifically pointed out that not all 14-bit or 16-bit A/Ds were created equal. In fact, that was essentially my main point.
I was simply trying to point out, without getting too verbose and technical, that there were different grades of A/Ds, and that it was certainly possible to get good quality A/Ds with relatively low noise figures, and poorer quality A/Ds with higher noise figures, all with the same bit depth. I wasn't making any absolute statements about the number of bits of noise present, since my whole point was that noise was a figure that varies greatly with different A/Ds. I was trying to make the point that just quoting bit depth was, by itself, somewhat meaningless, without also discussing the quality of the A/Ds involved.
The 2 to 4 bits that I mentioned several times was offered as an example of a relatively good, low noise A/D that still had the relatively high sample rate capabilities needed for imaging applications. You can certainly get lower noise A/Ds, but they also tend to be available only in lower sampling rates. My example was also based on a quick survey of a few suppliers I usually use in my designs (my day job). It wasn't an exhaustive survey. I ended up using a Linear Tech model as my example of a good, low noise, high sample rate A/D. I didn't look at TI models, and it's certainly possible they have something even better than the parts I looked at.
I'm sure I could have written my original post more clearly, but by the end of my second paragraph, I was already boring myself to tears :-)
In fact it is even conceivable that a poor quality 16 bit SDC will have a worse SNR than a 14 bit ADC.
Absoulutely true.
So at least we can agree that not all ADCs are created equal. It is quite possible for a stunning 14bit circuit to outperform a poor 16bit competitor.
Again, absolutely true. One other point I tried to make in my earlier post, however, is that given the higher costs of MFDBs, it is likely that the MFDB designers probably have a higher parts budget to work with than lower cost DSLR designers. And that, therefore, it was also likely that MFDBs use better quality A/Ds than DSLRs do. Which again tried to make my overall point that simply comparing bit depths was meaningless, without also knowing what kind of A/Ds were used. There are obviously a lot of conjectures in this last point, however, but hopefully I made that clear in my original comments.
Regards,
Mort.
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[attachment=7324:attachment]
true 9 colors roylgglccdcb sensor which increase its resolution without any interpolation.
( stands for red-orange-yelow-lightgreen-green-lightcyan-cyan-darkcyan-brown sensor )
[a href=\"index.php?act=findpost&pid=205331\"][{POST_SNAPBACK}][/a]
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You'd think that P1 would pad out the 2 least significant bits, even though this really doesn't have an impact in the real world unless you are stretching/pushing the files hard.
I don't know what to think of this issue. "Padding out" those bits amounts to the admission, that the camera delivers only 14 usable bits; I guess that must not happen b/c of marketing considerations.
Think of this:
1. When Edmund complained about the striations his P45+ images, the answer was, IIRC, that ISO 800 is not really meant to be used (I can't cite it literally, this was a post long ago).
2. After further insistance, his camera got replaced.
However, detail analysis reveals, that
a. the horizontal banding does not depend on ISO at all; obviously it occurs at a later stage,
b. the replacement camera is even worse than the first one was. I just took a look and found, that Edmund's first copy of P45+ created sensor artifacts in the *two* low order bits, invisible in the third bit, but the replacement camera shows this in the third low order bit as well (at ISO 100, though I do not think this makes any difference).
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just read this thread: you guys make me crack!
I'm so sorry I wasn't available to join the food and dimensionality orgy!
Cheers to all,
Thierry
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I certainly didn't mean to imply that, and thought I was quite clear that noise figures vary considerably across different A/Ds. I specifically pointed out that not all 14-bit or 16-bit A/Ds were created equal. In fact, that was essentially my main point.
I was simply trying to point out, without getting too verbose and technical, that there were different grades of A/Ds, and that it was certainly possible to get good quality A/Ds with relatively low noise figures, and poorer quality A/Ds with higher noise figures, all with the same bit depth. I wasn't making any absolute statements about the number of bits of noise present, since my whole point was that noise was a figure that varies greatly with different A/Ds. I was trying to make the point that just quoting bit depth was, by itself, somewhat meaningless, without also discussing the quality of the A/Ds involved.
The 2 to 4 bits that I mentioned several times was offered as an example of a relatively good, low noise A/D that still had the relatively high sample rate capabilities needed for imaging applications. You can certainly get lower noise A/Ds, but they also tend to be available only in lower sampling rates. My example was also based on a quick survey of a few suppliers I usually use in my designs (my day job). It wasn't an exhaustive survey. I ended up using a Linear Tech model as my example of a good, low noise, high sample rate A/D. I didn't look at TI models, and it's certainly possible they have something even better than the parts I looked at.
I'm sure I could have written my original post more clearly, but by the end of my second paragraph, I was already boring myself to tears :-)
Absoulutely true.
Again, absolutely true. One other point I tried to make in my earlier post, however, is that given the higher costs of MFDBs, it is likely that the MFDB designers probably have a higher parts budget to work with than lower cost DSLR designers. And that, therefore, it was also likely that MFDBs use better quality A/Ds than DSLRs do. Which again tried to make my overall point that simply comparing bit depths was meaningless, without also knowing what kind of A/Ds were used. There are obviously a lot of conjectures in this last point, however, but hopefully I made that clear in my original comments.
Regards,
Mort.
[a href=\"index.php?act=findpost&pid=205346\"][{POST_SNAPBACK}][/a]
Dear Mort and friends,
One should do side by side comparison between Canon 1dsm3 14 BIT and 16 bit Phase One P30+ of the same scene containing bright highlights and deep shadows with lots of colors (fruit and vegetables), in 100 ASA, in raw, same development, and should show enlargments 100% of side by side same area in order to show and convince which has better DR, lower noise and clearer distinct details in shadows and highlights, instead of bla, bla, bla.....and make unpopular the one that wants to know what camera to choose for his own jobs. so simple and elementary.
Declarations, assumptions and theories of self assurance, one sided photographers, are not a substitute of scientific real tests that everyone can see and judge.
Thanks,
Menachem Reiss. www.reiss.co.il
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Dear Mort and friends,
One should do side by side comparison between Canon 1dsm3 14 BIT and 16 bit Phase One P30+ of the same scene containing bright highlights and deep shadows with lots of colors (fruit and vegetables), in 100 ASA, in raw, same development, and should show enlargments 100% of side by side same area in order to show and convince which has better DR, lower noise and clearer distinct details in shadows and highlights, instead of bla, bla, bla.....and make unpopular the one that wants to know what camera to choose for his own jobs. so simple and elementary.
Declarations, assumptions and theories of self assurance, one sided photographers, are not a substitute of scientific real tests that everyone can see and judge.
Thanks,
Menachem Reiss. www.reiss.co.il
[a href=\"index.php?act=findpost&pid=205652\"][{POST_SNAPBACK}][/a]
My offer from the other thread to analyze MFDB's still stands:
Testing needn't be done side-by-side, current DSLR's have been analyzed already. Anyone with a MFDB they want tested should provide the following:
1. A pair of identical images of a colorchecker chart (GM is fine, others are probably OK too as long as the squares are big enough), slightly OOF and filling a large part of the frame; lens two stops down from wide open (to minimize vignetting but not to introduce dust bunnies); shot at the camera's base ISO (usually 100); metered properly. The images should be shot in succession, waiting for the buffer to clear before taking the second one. Tripod of course, fixed light source uniformly illuminating the target. Remotely actuated would be great.
2. Same as (1), but three stops overexposed relative to the metering for (1).
3. Same as (1) but three stops underexposed relative to the metering for (1).
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My offer from the other thread to analyze MFDB's still stands:
Testing needn't be done side-by-side, current DSLR's have been analyzed already. Anyone with a MFDB they want tested should provide the following:
1. A pair of identical images of a colorchecker chart (GM is fine, others are probably OK too as long as the squares are big enough), slightly OOF and filling a large part of the frame; lens two stops down from wide open (to minimize vignetting but not to introduce dust bunnies); shot at the camera's base ISO (usually 100); metered properly. The images should be shot in succession, waiting for the buffer to clear before taking the second one. Tripod of course, fixed light source uniformly illuminating the target. Remotely actuated would be great.
2. Same as (1), but three stops overexposed relative to the metering for (1).
3. Same as (1) but three stops underexposed relative to the metering for (1).
[a href=\"index.php?act=findpost&pid=205660\"][{POST_SNAPBACK}][/a]
Again if you want to be scientifically precise and not comparing photographers ability, light difference, dof and lens difference, than:
One should do side by side comparison between Canon 1dsm3 14 BIT and 16 bit Phase One P30+ of the same scene containing bright highlights and deep shadows with lots of colors (fruit and vegetables), in 100 ASA, in raw, same development, and should show enlargments 100% of side by side same area in order to show and convince which has better DR, lower noise and clearer distinct details in shadows and highlights, instead of blah, blah, blah.....and make unpopular the one that wants to know what camera to choose for his own jobs. so simple and elementary.
I agree to add to the side by side set: a colorchecker chart, GM is fine. three stops overexposed and three stops underexposed will add to see DR
One can shoot the Phase One P30+ in f: 4 and the 1dsm3 in F:2.8 (compensating for exposure) in one test in order to see 3D effect on both cameras (putting distant and suitable, nice background full of out of focus items).
Declarations, assumptions and theories of self assurance, one sided photographers, are not a substitute of scientific real tests that everyone can see and judge.
Thanks,
Menachem Reiss. www.reiss.co.il
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My offer from the other thread to analyze MFDB's still stands:
Testing needn't be done side-by-side, current DSLR's have been analyzed already. Anyone with a MFDB they want tested should provide the following:
1. A pair of identical images of a colorchecker chart (GM is fine, others are probably OK too as long as the squares are big enough), slightly OOF and filling a large part of the frame; lens two stops down from wide open (to minimize vignetting but not to introduce dust bunnies); shot at the camera's base ISO (usually 100); metered properly. The images should be shot in succession, waiting for the buffer to clear before taking the second one. Tripod of course, fixed light source uniformly illuminating the target. Remotely actuated would be great.
2. Same as (1), but three stops overexposed relative to the metering for (1).
3. Same as (1) but three stops underexposed relative to the metering for (1).
[a href=\"index.php?act=findpost&pid=205660\"][{POST_SNAPBACK}][/a]
Again if you want to be scientifically precise and not comparing photographers ability, light difference, dof and lens difference, than:
One should do side by side comparison between Canon 1dsm3 14 BIT and 16 bit Phase One P30+ of the same scene containing bright highlights and deep shadows with lots of colors (fruit and vegetables), in 100 ASA, in raw, same development, and should show enlargments 100% of side by side same area in order to show and convince which has better DR, lower noise and clearer distinct details in shadows and highlights, instead of blah, blah, blah.....and make unpopular the one that wants to know what camera to choose for his own jobs. so simple and elementary.
I agree to add to the side by side set: a colorchecker chart, GM is fine. three stops overexposed and three stops underexposed will add to see DR
One can shoot the Phase One P30+ in f: 4 and the 1dsm3 in F:2.8 (compensating for exposure) in one test in order to see 3D effect on both cameras (putting distant and suitable, nice background full of out of focus items).
Declarations, assumptions and theories of self assurance, one sided photographers, are not a substitute of scientific real tests that everyone can see and judge.
Thanks,
Menachem Reiss. www.reiss.co.il
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One should do side by side comparison between Canon 1dsm3 14 BIT and 16 bit
... same development,
[a href=\"index.php?act=findpost&pid=205652\"][{POST_SNAPBACK}][/a]
Not quite the same development, as (I believe) the resulting RAW files do not have the same tone curve. (I don't think they *are* 100% linear in RAW space...)
And, of course, who wants to find out just how much they might have overpaid? I remember the shock I received, comparing a 1Ds and G9 in good light and proper exposure.....
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(I believe) the resulting RAW files do not have the same tone curve. (I don't think they *are* 100% linear in RAW space...)
1. The raw data does not have any tone curves,
2. The individual color channels are originally linear. The interpretation by the raw processor can (and sometimes does) introduce some small degree of non-linearity, but you have no way of compensating for that, i.e. you have no choice but regard the result as linear and curse if it is not.
In order to verify this, shoot different shades of the *very same gray* (like on a color checker), pick WB on the white and check how gray the darker ones are.
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Dear Mort and friends,
One should do side by side comparison between Canon 1dsm3 14 BIT and 16 bit Phase One P30+ of the same scene containing bright highlights and deep shadows with lots of colors (fruit and vegetables), in 100 ASA, in raw, same development, and should show enlargments 100% of side by side same area in order to show and convince which has better DR, lower noise and clearer distinct details in shadows and highlights, instead of bla, bla, bla.....and make unpopular the one that wants to know what camera to choose for his own jobs. so simple and elementary.
Declarations, assumptions and theories of self assurance, one sided photographers, are not a substitute of scientific real tests that everyone can see and judge.
I could care less what camera someone wants to use. That's a personal choice based on their own particular needs. If you think your 1DsIII is better than a MFDB, then great, enjoy your camera. I personally have both a DSLR and a MFDB, and enjoy using both. They each have their strengths and weaknesses.
As for proving anything to you or anyone else, why should we? You're the one coming to the MF forum and making these claims. The burden of proof is on you. Why don't YOU put together side by side shots, of fruit and such, and show 100% crops, bla, bla, bla. Most of the people on here who have MFDBs also have DSLRs, so we already know what out backs and !dsIII's and D3's will and won't do, and have a pretty good feel for how they compare. So the ball is in your court. If you think DSLRs are as good as or better than MFDBs, feel free to prove it. Or better yet, just put what you have to good use and don't dwell on which is better at this or that.
Regards,
Mort.
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Again if you want to be scientifically precise and not comparing photographers ability, light difference, dof and lens difference, than:
One should do side by side comparison between Canon 1dsm3 14 BIT and 16 bit Phase One P30+ of the same scene containing bright highlights and deep shadows with lots of colors (fruit and vegetables), in 100 ASA, in raw, same development, and should show enlargments 100% of side by side same area in order to show and convince which has better DR, lower noise and clearer distinct details in shadows and highlights, instead of blah, blah, blah.....and make unpopular the one that wants to know what camera to choose for his own jobs. so simple and elementary.
I agree to add to the side by side set: a colorchecker chart, GM is fine. three stops overexposed and three stops underexposed will add to see DR
One can shoot the Phase One P30+ in f: 4 and the 1dsm3 in F:2.8 (compensating for exposure) in one test in order to see 3D effect on both cameras (putting distant and suitable, nice background full of out of focus items).
Declarations, assumptions and theories of self assurance, one sided photographers, are not a substitute of scientific real tests that everyone can see and judge.
Thanks,
Menachem Reiss. www.reiss.co.il
[a href=\"index.php?act=findpost&pid=205667\"][{POST_SNAPBACK}][/a]
I am after measuring the pixel "gain" (photons/raw level) and read noise. From these, S/N characteristics as a function of exposure and dynamic range are entirely determined. One does not need to have the cameras side by side in order to measure these quantitative properties. I spelled out the test conditions so that photographic ability is not part of the equation -- unless someone has trouble getting an out-of-focus image of a GMCC chart ;-)
As I mentioned, this exercise has already been done for the relevant DSLR's (Canon 1 series and Nikon D3). Perhaps it has been done as well for some MFDB's, but if so I have not seen the relevant data reported anywhere.
As for the supposed "3D effect", I'm not trying to isolate that.
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I am after measuring the pixel "gain" (photons/raw level) and read noise. From these, S/N characteristics as a function of exposure and dynamic range are entirely determined. One does not need to have the cameras side by side in order to measure these quantitative properties. I spelled out the test conditions so that photographic ability is not part of the equation -- unless someone has trouble getting an out-of-focus image of a GMCC chart ;-)
As I mentioned, this exercise has already been done for the relevant DSLR's (Canon 1 series and Nikon D3). Perhaps it has been done as well for some MFDB's, but if so I have not seen the relevant data reported anywhere.
[a href=\"index.php?act=findpost&pid=205767\"][{POST_SNAPBACK}][/a]
Kodak and Dalsa do publish the specs for many of the sensors used in MFDBs. For example, the Kodak KAF 39000 has a pixel spacing of 6.8 microns, full well capacity of 60K electrons, and a read noise of 16 electrons at a certain reading speed and unspecified ISO. The quoted read noise is not particularly impressive and it would be interesting to see the KAF 39000 tested under the same conditions as the Nikon and Canon sensors you mention. The KAF 39000 has more pixels than Canon or Nikon, but it remains to be seen if the great dynamic range boasted by the MFDB crowd is real or imagined.
Of course the ADC is external to the sensor in a CCD design, and the digital back maker could use a low read speed and a high bit, high quality ADC to improve performance. One doesn't shoot at 10 frames/second with a MFDB.
Bill
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Kodak and Dalsa do publish the specs for many of the sensors used in MFDBs. For example, the Kodak KAF 39000 has a pixel spacing of 6.8 microns, full well capacity of 60K electrons, and a read noise of 16 electrons at a certain reading speed and unspecified ISO. The quoted read noise is not particularly impressive and it would be interesting to see the KAF 39000 tested under the same conditions as the Nikon and Canon sensors you mention. The KAF 39000 has more pixels than Canon or Nikon, but it remains to be seen if the great dynamic range boasted by the MFDB crowd is real or imagined.
Of course the ADC is external to the sensor in a CCD design, and the digital back maker could use a low read speed and a high bit, high quality ADC to improve performance. One doesn't shoot at 10 frames/second with a MFDB.
Bill
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It would indeed be interesting if someone were to do the legwork on the sensors (hint ). Who uses the KAF 39000? The sensor DR bounds the overall DR; already with this sensor 39000/16=3750~11.9 stops, realized DR after amplification and ADC quantization will surely be less. 16 bits is really of no help there, except insofar as one wants to cut down on quantization error when all ISO is implemented in software during post-processing.
BTW, if we are talking purely about sensor properties, according to Bart van der Wolf
[a href=\"http://www.openphotographyforums.com/forums/showthread.php?t=4784]http://www.openphotographyforums.com/forum...read.php?t=4784[/url]
http://www.openphotographyforums.com/forum...read.php?t=4771 (http://www.openphotographyforums.com/forums/showthread.php?t=4771)
the 1Ds3 sensor has a full well capacity of about 57000 electrons, and a read noise of about 5 electrons (best measured at ISO 1600, where components downstream of the sensor contribute negligibly to read noise). Thus the 1D3 sensor's DR is 57000/5=11400~13.5 stops.
Now, to be fair, the noise in the downstream components is such that Canon is unable to realize this DR at base ISO in practice, losing about two stops in read noise due to amplifier and ADC noise at ISO 100 (though I think they could if they were a little smarter about the design, by running two amplifiers in parallel and then combining the results, as I have described elsewhere).
There is also the issue of how quickly the sensor climbs up out of the read noise dominated territory, which bears on shadow IQ, and that is where larger formats really come into their own.
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the 1Ds3 sensor has a full well capacity of about 57000 electrons, and a read noise of about 5 electrons (best measured at ISO 1600, where components downstream of the sensor contribute negligibly to read noise). Thus the 1D3 sensor's DR is 57000/5=11400~13.5 stops.
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Emil,
When calculating the DR at full well, why do you use the read noise for ISO 1600? Or is the read noise at base ISO that low?
Bill
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Emil,
When calculating the DR at full well, why do you use the read noise for ISO 1600? Or is the read noise at base ISO that low?
Bill
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=206064\")
I used to think this was goofy, but now I know better (and finally understand what Roger Clark has been trying to say for a long time). The read noise in absolute terms (eg in photoelectron equivalents) is much higher at base ISO, but this fact is due to the electronics downstream of the sensor (the variable gain amplifier that implements ISO, and the ADC) rather than the noise of the sensor capture itself. One can see that from the plots of read noise vs ISO at
[a href=\"http://theory.uchicago.edu/~ejm/pix/20d/tests/noise/noise-p2.html#read_vs_iso]http://theory.uchicago.edu/~ejm/pix/20d/te...tml#read_vs_iso[/url]
See in particular the little table below fig 15. The sensor noise is amplified by the ISO amplification, which is why high ISO read noise is large in ADU, but low when referred back to photoelectrons. The low ISO read noise is small in ADU, but large when referred back to photoelectrons; the amplifier/ADC noise is independent of ISO when denominated in ADU. So the dominant contribution to read noise at low ISO comes from the ISO amplifier and ADC, while at high ISO it is almost entirely due to the photosite electronics. What this means is that the read noise at low ISO is being limited by the amplifier/ADC components, since if they contributed less than the sensor itself, one would get the full DR of the sensor.
This is why Roger Clark is careful to distinguish what he calls "sensor DR" from "camera DR". The former is about 14 stops, while the latter is a bit under 12 stops for the 1D3/1Ds3. The difference is due to the quality/capability of the electronics downstream of the sensor in Canon cameras (and also the D3/D300, I should add).
One then might ask, so what? Won't the electronics downstream of the sensor always limit the DR in this way? I don't think so. In principle one could take the sensor output and run it through two parallel signal processing routes -- one set to ISO 100 and the other set to ISO 1600 (think of it as "in-camera HDR"). The low ISO path captures the highlights, but has four times the read noise in electrons. The high ISO path has the highlights clipped, but that's OK we're going to take those from the other path anyway; instead, the high ISO path captures the shadows with much lower read noise in electrons. After digitisation, the two paths can be combined in much the same way one combines two exposures in HDR, one for highlights and the other for shadows. It would be trivial to code this, the only cost is the extra hardware for the dual amplifications. And since one is always capturing the full DR that the sensor can deliver, there is no reason whatsoever to have variable gain; ISO can be implemented as it is in many MFDB's, as a metadata tag for the raw converter to apply. The difference is that one would actually have about 14 stops of DR and high bit depth would actually be justified for a change.
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In principle one could take the sensor output and run it through two parallel signal processing routes -- one set to ISO 100 and the other set to ISO 1600 (think of it as "in-camera HDR
Don't you think this *is* the way most MFDBs work? (The Phase One P45+ is rather the exception.)
This is, what I meant earlier, when saying that the lack of different ISO gains is an advantage, although some MFDB owners are upset by the "accusation", that their ISO selection is placebo.
I want a cropping camera with "uni-ISO".
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Don't you think this *is* the way most MFDBs work? (The Phase One P45+ is rather the exception.)
This is, what I meant earlier, when saying that the lack of different ISO gains is an advantage, although some MFDB owners are upset by the "accusation", that their ISO selection is placebo.
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I have no evidence one way or the other as to whether MFDB's use such dual processing. It would be easy to diagnose in the raw data however, I just haven't had enough examples to examine as yet. I would be surprised however if they used this sort of dual amplification scheme; it's more likely that they spend the money to have lower noise amplifiers, higher DR ADC's etc so as to make such a scheme superfluous, with the DR limited by the sensor. It's not so hard if the sensor DR is less than twelve stops anyway.
I do agree that, insofar as the signal processing chain is limited by the sensor's DR rather than that of the rest of the electronics, there is no need to have variable ISO gain as one does on DSLR's currently. Variable gain is not needed if the raw data contains all the data that the sensor is recording, regardless of exposure.
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there is no need to have variable ISO gain as one does on DSLR's currently. Variable gain is not needed if the raw data contains all the data that the sensor is recording, regardless of exposure.
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Analog ISO gain is useful as it provides the "dithering" via noise amplification -- something similar to the reduction of perception of harmonic distortion in audio ADC is accomplished by adding random dither signal before digitization. OTOH, compensating a lack of analog gain by digital gain (say software) results in posterization in certain low light scenes.
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I used to think this was goofy, but now I know better (and finally understand what Roger Clark has been trying to say for a long time).
This is why Roger Clark is careful to distinguish what he calls "sensor DR" from "camera DR". The former is about 14 stops, while the latter is a bit under 12 stops for the 1D3/1Ds3. The difference is due to the quality/capability of the electronics downstream of the sensor in Canon cameras (and also the D3/D300, I should add).
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Emil,
Thanks for the detailed explanation. It all makes good sense. However, when one is taking pictures, it is the camera DR that is most important. When Kodak rates the KAF 39000 DR at 71.4 dB or 11.9 stops, that is the sensor DR and the camera DR would be less. The question is: less by how much with the best possible electronics downstream from the sensor.
Bill
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Analog ISO gain is useful as it provides the "dithering" via noise amplification -- something similar to the reduction of perception of harmonic distortion in audio ADC is accomplished by adding random dither signal before digitization. OTOH, compensating a lack of analog gain by digital gain (say software) results in posterization in certain low light scenes.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=206101\")
As long as the noise sufficiently exceeds the quantization step, posterization will not occur:
[a href=\"http://theory.uchicago.edu/~ejm/pix/20d/tests/noise/noise-p3.html]http://theory.uchicago.edu/~ejm/pix/20d/te...e/noise-p3.html[/url]
The dithering provided by the sensor electronics will be quite enough, provided the bit depth of the ADC is chosen appropriately; there is no need to introduce additional noise downstream of the sensor, it just further degrades the signal.
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As long as the noise sufficiently exceeds the quantization step, posterization will not occur:
http://theory.uchicago.edu/~ejm/pix/20d/te...e/noise-p3.html (http://theory.uchicago.edu/~ejm/pix/20d/tests/noise/noise-p3.html)
The dithering provided by the sensor electronics will be quite enough, provided the bit depth of the ADC is chosen appropriately; there is no need to introduce additional noise downstream of the sensor, it just further degrades the signal.
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Thanks for the link. You have good information. The section entitled "An aside on "lossy" NEF compression" seems like the time-honored analog-domain well-known techniques of applying concave non-linearities to signal to boost signal to noise ratio over linear quantization.
Back to topic. Unfortunately, one does not always have the choice of matching bit depth of ADC to control the posterization. We have seen standard sensors do bad posterization under low-light condition and analog amplification of noise via ISO gain has been our good friend vs. digital ISO gain.
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Unfortunately, one does not always have the choice of matching bit depth of ADC to control the posterization
What about the new Nikons with selectable bit depth?
Though I have the feeling, that internally it is always 14bit.
We have seen standard sensors do bad posterization under low-light condition and analog amplification of noise via ISO gain has been our good friend vs. digital ISO gain
Are you referring to the "plain" digital gain (multiplying the pixel values by some constant), or do you think that the amplified noise is inherently better than for example two randomly generated low order bits?
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What about the new Nikons with selectable bit depth?
I have to look into the new Nikons that you mention.
Are you referring to the "plain" digital gain (multiplying the pixel values by some constant), or do you think that the amplified noise is inherently better than for example two randomly generated low order bits?
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Adding noise after quantization is not as effective as adding noise before quantization. Hence, randomly generated low order bits may not give as good a response as higher analog gain (for noise amplification) before quantization.
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Adding noise after quantization is not as effective as adding noise before quantization
Why not? What makes one random value more effective than another one?
Btw, what is the measure of "effectivity" in this regard?
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Thanks for the link. You have good information. The section entitled "An aside on "lossy" NEF compression" seems like the time-honored analog-domain well-known techniques of applying concave non-linearities to signal to boost signal to noise ratio over linear quantization.
Back to topic. Unfortunately, one does not always have the choice of matching bit depth of ADC to control the posterization. We have seen standard sensors do bad posterization under low-light condition and analog amplification of noise via ISO gain has been our good friend vs. digital ISO gain.
[{POST_SNAPBACK}][/a] (http://index.php?act=findpost&pid=206298\")
Do you have an example to show? It is possible that if there is posterization, it is being introduced by the algorithm of raw conversion rather than being intrinsic to the raw data itself. For instance, raw data that is not posterized can be made posterized by median filtering, a common technique for reducing noise:
[a href=\"http://forums.dpreview.com/forums/read.asp?forum=1021&message=28139198]http://forums.dpreview.com/forums/read.asp...essage=28139198[/url]
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Why not? What makes one random value more effective than another one?
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Adding noise to posterized data makes noisy posterized data. Noise present before quantization dithers the tonal transitions and eliminates the posterization.
It's easy enough to check this for yourself. Make a tonal gradient in photoshop. Add N levels of gaussian noise. Now try to posterize it via two successive levels adjustments, the first reducing the maximum output level to 255/N, the second setting the max input level to 255/N (this has the effect of approximately dividing the levels by N and then multiplying them back up by N; the result in integer math that photoshop uses is to increase the gap in the level spacing by a factor N). Then do the same exercise, adding the noise after the two levels adjustments. Adding noise after the posterization is MUCH less effective in masking the posterization.
Why is this so? Because adding the noise after quantization does not change the mean of the pixels in a given posterized region. Adding the noise before quantization results in a smooth modulation of the percentage of pixels having one quantized level vs the next one; the eye averages over spatial regions and the average of the pixel values reflects the original smooth tonal variation over space. And this is the way dithering works -- it trades spatial resolution for smoother tonal transitions.
[a href=\"http://en.wikipedia.org/wiki/Dithering]http://en.wikipedia.org/wiki/Dithering[/url]
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Why not? What makes one random value more effective than another one?
In regions of low-luminance gradients or contours, the input random noise causes the pixels to go above or below the original decision level (via quantization). The effects is to "break" the contouring. However, the averaged value of the quantized pixels is about the same with and without the additive noise.
If noise is not added before quantization then higher levels of added noise after quantization may be required to hide the contouring resulting in overall worse picture.
Btw, what is the measure of "effectivity" in this regard?
[a href=\"index.php?act=findpost&pid=206314\"][{POST_SNAPBACK}][/a]
Measured as the trade off between the output variance in intensity from the mean value of the output in a portion of the picture which was of constant intensity at the input averaged over all inputs, and the deviation of mean output from the input.
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Do you have an example to show?
Unfortunately, I can't post them here.
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Thanks, gentlemen, that's what I wanted to hear.
I register with satisfaction your arguments
1. for the greater bit depth even if the "excess" bits represent only noise,
2. again lossy compression of raw files.
Now we can move on and forget all formerly said nonsense about how harmless Nikon's lossy compression is.
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Two more comments on dither:
(1) Previously when I mentioned the below:
Btw, what is the measure of "effectivity" in this regard?
[a href=\"index.php?act=findpost&pid=206314\"][{POST_SNAPBACK}][/a]
Measured as the trade off between the output variance in intensity from the mean value of the output in a portion of the picture which was of constant intensity at the input averaged over all inputs, and the deviation of mean output from the input.
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The sum of the "variance" quantity (sometimes called apparent noise) and the "deviation" quantity (sometimes called tonal quality) defines the reconstruction error variance. Degradation represented by tonal quality is perceptually more annoying, and hence, a good quantization scheme should seek to decrease tonal quality degradation, at the expense of apparent noise, such that the total reconstruction error is minimized.
And, adding dither signal before quantization helps us to accomplish the above, i.e., lowering tonal quality degradation, for a more pleasing image.
(2) The dither signal does not always have to be random. It can be deterministic under certain situations, and in those circumstances may actually be better than random dither.
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Thanks, gentlemen, that's what I wanted to hear.
I register with satisfaction your arguments
1. for the greater bit depth even if the "excess" bits represent only noise,
2. again lossy compression of raw files.
Now we can move on and forget all formerly said nonsense about how harmless Nikon's lossy compression is.
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You mean what you thought you heard because you wanted to hear it.
What both joofa and I actually pointed out was that noise present before quantization masks posterization up to the level of the noise. This is the basic argument why bit depth need not exceed DR (or locally, quantization step need not be substantially less than S/N ratio), which you continue to fail to grasp.
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Measured as the trade off between the output variance in intensity from the mean value of the output in a portion of the picture which was of constant intensity at the input averaged over all inputs, and the deviation of mean output from the input.
[a href=\"index.php?act=findpost&pid=206339\"][{POST_SNAPBACK}][/a]
I must say this is the sort of thing that gets me excited about photography all over again
Nick-T
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When I read this:
"Measured as the trade off between the output variance in intensity from the mean value of the output in a portion of the picture which was of constant intensity at the input averaged over all inputs, and the deviation of mean output from the input."
It moved. I mean IT.
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Sorry guys. I shall tone down from next time. I think I got carried away with the excitement that engulfs a new member.
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...got carried away with the excitement that engulfs a new member...
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Definitely not going to touch this one.